This invention relates generally to dishwashers and, more particularly, to methods and appliances for circulating fluid in dishwashers.
Conventional dishwasher systems include a main pump assembly and a drain pump assembly for circulating and draining wash fluid, respectively, within a wash chamber defined within the dishwasher system. The main pump assembly feeds wash fluid to various spray arm assemblies for distribution throughout the wash chamber to wash soiled items loaded into dishwasher racks positioned within the wash chamber. Wash fluid sprayed onto the dishwasher items is collected in a sump located in a lower portion of the wash chamber, and water entering the sump is filtered through one or more coarse filters to remove soil and/or sediment from the wash fluid. At least some conventional dishwasher systems further include a filter system in flow communication with the main pump assembly to remove soil and/or sediment of a smaller particle size than those particles filtered by the coarse filters. The main pump assembly draws wash fluid from the sump to re-circulate in the wash chamber, and the coarse and fine filters are used to continuously filter the water in the sump during the re-circulation process. However, a drain pump and a main pump occupy a considerable amount of space within the dishwasher and increase the manufacture cost.